从.cer文件生成公钥在Android28上不起作用

import java.io.InputStream;
import java.security.KeyFactory;
import java.security.PublicKey;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;

public class PublicKeyExtractor {
    public static PublicKey extractPublicKey(InputStream certificateInputStream) {
        try {
            CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
            X509Certificate certificate = (X509Certificate) certificateFactory.generateCertificate(certificateInputStream);
            return certificate.getPublicKey();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}